In vitro age-related responses of endothelial cells to breast cancer cell addition

Influence of L1-CAM expression of breast cancer cells on adhesion to endothelial cells

PURPOSE

Expression of the adhesion molecule L1-CAM (L1) has been shown to correlate with early recurrence in breast cancer. Here, we investigated whether L1-CAM expression of breast cancer cells might influence adherence to human pulmonary microvascular endothelial cells (HPMEC) and thus promote metastasis.

METHODS

MDA-MB231-Fra2 breast cancer cells that express high levels of L1-CAM (L1(high) cells) were stably transfected to generate clones with strong L1-CAM downregulation. Adhesion to activated HPMEC was studied in dynamic cell flow and static assays. Potential binding partners on endothelial cells were identified by blocking experiments and adhesion assays after coating of the flow channels with recombinant proteins.

RESULTS

Adhesion of L1(high) cells to activated HPMEC was significantly higher compared to L1l(ow) clones under flow conditions. Blocking experiments and adhesion assays with recombinant proteins identified activated leucocyte cell adhesion molecule (ALCAM) or L1 itself, but not ICAM-1, as potential binding partners on endothelial cells. E-selectin blocking antibodies strongly diminished the adherence of breast cancer cells irrespective of their L1-CAM expression.

CONCLUSIONS

Our experiments indicate that L1-CAM expression on breast cancer cells can promote adherence to activated endothelial cells by binding to endothelial L1-CAM or ALCAM. This mechanism might lead to increased metastasis and a poor prognosis in L1-CAM-positive carcinomas in vivo. Therefore, L1-CAM might be a suitable therapeutic target in breast cancers with a high L1-CAM expression.

Cell culture models using rat primary alveolar type I cells

There is a lack of cell culture models using primary alveolar type I (AT I) cells. The purpose of this study was to develop cell culture models using rat AT I cells and microvascular endothelial cells from the lung (MVECL). Two types of model systems were developed: single and co-culture systems; additionally a 3-dimensional model system was developed. Pure AT I cell (96.3 ± 2.7%) and MVECL (97.9 ± 1.1%) preparations were used. AT I cell morphology, mitochondrial number and distribution, actin filament arrangement and number of apoptotic cells at confluence, and telomere attrition were characterized. AT I cells maintained their morphometric characteristics through at least population doubling (PD) 35, while demonstrating telomere attrition through at least PD 100. Furthermore, AT I cells maintained the expression of their specific markers, T1α and AQ-5, through PD 42. For the co-cultures, AT I cells were grown on the top and MVECL were grown on the bottom of fibronectin-coated 24-well Transwell Fluroblok™ filter inserts. Neither cell type transmigrated the 1 μm pores. Additionally, AT I cells were grown in a thick layer of Matrigel(®) to create a 3-dimensional model in which primary AT I cells form ring-like structures that resemble an alveolus. The development of these model systems offers the opportunities to investigate AT I cells and their interactions with MVECL in response to pharmacological interventions and in the processes of disease, repair and regeneration.

Immunological methods for nursing research: from cells to systems

Scientists and clinicians frequently use immunological methods (IMs) to investigate complex biological phenomena. Commonly used IMs include immunocytochemistry (IC), enzyme-linked immunosorbent assays (ELISA) and flow cytometry. Each of these methodologies exploits a common principle in IMs -the binding of an antibody to its antigen. Scientists continue to develop new methodologies, such as high-throughput immunohistochemistry (IHC) and in vivo imaging techniques, which exploit antibody-antigen binding, to more accurately answer complex research questions involving single cells up to whole organ systems. The purpose of this paper is to discuss established and evolving IMs and to illustrate the application of these methods to nursing research.